title: Computational evidence for heavy-atom tunneling in the bergman cyclization of a 10-membered-ring enediyne.
abstract: DFT and CASSCF calculations for the cyclization of (3Z)-cyclodec-3-en-1,5-diyne were carried out to investigate heavy-atom tunneling. At 37 °C, tunneling was computed to enhance the rate by 38-40% over the transition-state theory rate. Intramolecular (12)C/(13)C kinetic isotope effects were predicted to be substantial, with a steep temperature dependence. These results are discussed in relation to recent experimental findings that show heavy-atom tunneling at moderate temperatures. The calculations point to the possibility of a simple computational test for the likelihood of heavy-atom tunneling using standard quantum-chemical information.
authors.affiliation: Department of Natural Sciences, Baruch College of the City University of New York, 17 Lexington Avenue, New York, New York 10010, United States. edyta.greer@baruch.cuny.edu
authors.forename: Edyta M
authors.initials: EM
authors.lastname: Greer
authors.forename: Christopher V
authors.initials: CV
authors.lastname: Cosgriff
authors.forename: Charles
authors.initials: C
authors.lastname: Doubleday
mesh_terms: D003500:Cyclization; D053281:Enediynes / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D011789:Quantum Theory
chemical_list: D053281:Enediynes